Synthesis of Tricyclic Laddersiloxanes 8-8-8-Membered Fused Rings

SYNTHESIS OF TRICYCLIC LADDERSILOXANES (6-8-6-MEMBERED FUSED RINGS) 

In this section we will describe the synthesis of tricyclic 6-8-6-membered rings laddersiloxane that is most easily accessed of the whole family. Thus, all-cis-[PhSi(0H)0]4 was treated with 

A 100 mb two-necked round flask, dropping funnel, Dimroth condenser, oil bath, separating funnel, filter funnel, magnetic stirrer, safety glasses, laboratory coat, and protective gloves. 

All-ds-[i-PrSi(OH)0]4 (synthesized (4)), Ph2SiCl2, NEts (distilled), CHCI3, sat.NH4Claq, brine, THE (distilled), anhydrous Na2S04, water, MeOH, EtOH, hexane. 

Dichlorodiphenylsilane (2.6 g, 10 mmol) in THE (25 mL) was added dropwise to a solution of all-ds-[i-PrSi(OH)0]4 (2.8 g, 5.1 mmol) and triethylamine (2.1 g, 21 mmol) in THE (15 mL) at 0°C under argon atmosphere. The mixture was refluxed for one day. To the reaction mixture, CHCI3 was added and the organic phase was washed with a saturated ammonium chloride aqueous solution and brine. The organic phase was dried over anhydrous sodium sulfate and concentrated to afford a crude solid, which was washed with methanol and ethanol. The solid was further purified by trituration with CHCI3 and hexane to afford laddersiloxane (1.8 g, 40%) as a white solid. 

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Synthesis of Tricyclic Laddersiloxanes (6-8-6-Membered Fused Rings) 436... 

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